A compound is a substance made up of two or more different elements chemically combined in a fixed ratio. Unlike elements, which are made up of only one type of atom, compounds are made up of two or more different types of atoms chemically bonded together.
Compounds can be classified into several categories, including ionic compounds and covalent compounds. Ionic compounds are composed of positively charged ions (called cations) and negatively charged ions (called anions) held together by ionic bonds. Covalent compounds are composed of non-metallic elements bonded together by covalent bonds, in which electrons are shared between atoms.
Compounds have unique chemical and physical properties that are different from those of the elements that make them up. For example, water (H2O) is a compound made up of hydrogen and oxygen. Water has properties, such as boiling and freezing points, that are different from those of hydrogen and oxygen individually.
Compounds play an important role in many aspects of our daily lives, including the substances used in food, medicine, and consumer goods. They are also used in a variety of industrial processes, such as energy generation and manufacturing.